
CAVE: This dataset [1]} consists of 32 images, each of size \(512 \times 512\)  and 31 spectral bands (\(400-700\)  nm).
We simulated the spectral response \(\mathbf {R}\)  following the protocol in [2]}, [3]} which was used to generate \(\mathbf {Y}_h\) ; \(\mathbf {Y}_\ell \)  was obtained by \(32\times \)  downsampling of the ground-truth.

HS+MS: We considered two datasets. The Pavia dataset has 115 spectral bands (\(0.43-0.86\)  \(\mu \) m) and a spatial resolution of \(1.3\) m. To simulate the \(\mathbf {Y}_\ell \)  image, we spatially blurred the ground-truth using the Starck–Murtagh filter [4]} and then downsampled the result by \(4\times \)  along both directions. To create the \(\mathbf {Y}_h\)  image (4 bands), the spectral response of IKONOS satellite was used. The Chikusei data set consists of HS images with 128 bands (\(0.36 - 1.018\)  \(\mu \) m) and MS images with 9 bands. The \(\mathbf {Y}_\ell \)  image is created similar to the Pavia dataset but with a \(6\times \)  downsampling. The spectral response \(\mathbf {R}\)  is estimated using the technique in [5]}. We conducted experiments on an HS image of size \(50 \times 50 \times 93\)  (93 bands and \(50 \times 50\)  resolution) and an MS image of size \(200 \times 200 \times 4\)  from the Pavia dataset. The size of the HS and MS images for Chikusei are \(30 \times 30 \times 128\) 
and \(180 \times 180 \times 9\) . Both \(\text{SNR}_h\)  and \(\text{SNR}_\ell \)  was set at 25dB for Pavia and at 20dB for Chikusei.

MS+PAN: For pansharpening, we considered the Pléiades dataset, where each MS image is of 60 cm resolution and has four bands (RGB and NIR). The size of the panchromatic and MS images are \(5000 \times 20000\)  and \(1250 \times 5000\) .
The spectral response was estimated as in [5]}, and the Starck–Murtaghh filter [4]} was used for the spatial blur.
We cropped the dataset into 5 non-overlapping regions of size \(256 \times 256\) , conducted the experiments on them individually, and averaged the results.

